The UN is a multilateral body with its main aim to assure another world war does not occur for future generations. Over the years international diplomacy has developed conventions, acts, bills, rules, and much more literature in regards to the benefit of humanity.
Without pointing fingers at the bullies of the world courts, let us examine a legal description and what is befitting to it.
Rome Statute of the International Criminal Court
As per Article 7, Crimes Against Humanity, any of the following acts when committed as part of a widespread or systematic attack directed against any civilian population, with